It's only an outrage when the US does it.
You are missing the point. The Brits spying on Americans and the Americans spying on Brits allow each county allows each county to spy on the own citizens carte blanche. When Obama says, “We are not listening to your phone calls (Brits are doing it for us). We are not gathering your emails without due process (Brits are doing it for us), etc...”
The story is how both countries are evading each others constitutional and privacy laws. By the way, when Obama says they are not listening to our phone calls, technically he is correct. That is too labor intensive. They translate the phone calls using voice-to-text software and store / run algorithms on every conversation in America.